Weighing Device for a Packaging Machine

ABSTRACT

The invention relates to a weighing device for a packaging machine. Empty capsules that are still closed are removed from a capsule holder, weighed on a gravimetric scale, placed back into an empty capsule holder, and then taken apart. The device makes it possible to remove empty capsules and replace them at full machine speed, without a loss of any consequence in output. It is possible to use a gravimetric measurement method to carry out a tare weighing of the capsules. An additional weighing device for filled capsules is integrated into a capsule transport device to determine the net weight based on the tare weight and the weight of the full capsules. Such a combination of a gravimetric tare weighing and a gross weighing to statistically determine the net weight is particularly well-suited to an intermediate capsule filling device.

PRIOR ART

The invention relates to a weighing device for a packaging machine, as generically defined by the preamble to claim 1.

DE 100 01 068 C1 has already disclosed a device for metering and dispensing powder into hard gelatin capsules or the like. As tamping pins descend into bores, they compress the powder, which is to be packaged, into pellets. In order to be able to obtain information about the mass of the pellets, means are provided that detect the spring path of the tamping pin directly preceding the ejecting pin.

In the capsule filling machines currently in use, usually the capsules are weighed after being filled, i.e. the combined weight of the capsule and filling (gross weight) is determined in order to check whether the filling quantity is correct. There are several methods for accomplishing this, e.g. weighing with a scale, weight determination through other physical effects, etc. using the statistical method or up to 100%. This method is imprecise due to a significant variance in weight of the empty capsules. There are also known methods in which the net weight is determined by a gross minus tare calculation. In these methods, capacitive physical effects are used, an approach that involves significant inaccuracies that are contingent on the system.

The object of the present invention is to eliminate or at least mitigate the above-mentioned disadvantages. This object is attained by the defining characteristics of the independent claims.

DISCLOSURE OF THE INVENTION

The device and method according to the defining characteristics of the independent claims increase the precision of the weight determination since they make it possible to eliminate imprecise capacitive methods for net weight determination. In addition, the capsules can be reliably and quickly removed, for example for weight determination, since at least one transport pin acts on the underside of the capsule and serves as a support during the removal of at least one capsule.

Other suitable embodiments ensue from additional dependent claims and the description.

DRAWINGS

An exemplary embodiment of the invention is shown in the drawings and will be explained in detail in the subsequent description.

FIG. 1 shows the arrangement of stations of a packaging machine, with transfer devices and weighing devices,

FIG. 2 is a side view of a transfer device with a capsule holder at station 3,

FIG. 3 shows the transfer device with the capsule holder, with the transfer device lowered.

FIG. 4 shows the transfer device with the capsule holder during upward capsule transport,

FIG. 5 shows the transfer device with the capsule holder during upward capsule transport, with support provided by the transport pins,

FIG. 6 shows the pivoting of the transfer device with suction applied to the capsules,

FIG. 7 is a top view of the transfer device, capsule holder, and weighing device,

FIG. 8 is a side view of the transfer device in connection with the weighing device,

FIG. 9 shows the transfer device as the capsules are being lowered onto the weighing dish of the weighing device,

FIG. 10 shows the depositing of the first capsule onto the weighing dish,

FIG. 11 shows the raising of the lifting device with the rest of the capsules,

FIG. 12 shows the depositing of the second capsule,

FIG. 13 shows the raising of the rest of the capsules and the weighing of the remaining two capsules,

FIG. 14 shows the weighing of all of the capsules.

A machine for filling and closing capsules 30 composed of a capsule bottom and a cap slid onto it has a twelve-part advancing wheel 20 that is rotated in steps around a vertical axis, with the individual handling devices situated at the stations 1 through 12 along the circumferential path of the wheel. At 1, the empty capsules 30 to be filled are loaded in a randomly ordered fashion, aligned, and then placed in an ordered fashion onto a capsule holder 21 of an advancing wheel 20. The capsules, which are still closed, are then removed from the capsule holder 21, weighed by a weighing device 22, then placed back into an empty capsule holder 21, and then the caps are removed from the bottoms. At 5, the filling, e.g. a powdered pharmaceutical product, is dispensed into the capsule bottoms. At 6, a weight testing system 16 checks the filling that has been dispensed into the capsule bottoms. At station 8, the capsules 30 are closed again. At 9, the gross weight of the filled capsules is determined by an additional weighing device 26. At 10, the capsules 30 are sealed, and at the subsequent station 1, they are ejected.

The invention describes how empty capsules 30 that are still closed can be removed from the capsule holder 21, weighed on a gravimetric scale 22, then placed back into an empty capsule holder 21, and taken apart. This device makes it possible to remove empty capsules 30 and replace them at full machine speed, without a loss of any consequence in output. It is possible to use a gravimetric measurement method to carry out a tare weighing of the capsules 30. If the additional weighing device 26 for filled capsules 30 is integrated into the capsule transport, it is then possible to determine the net weight based on the tare weight and the weight of the full capsules 30. Such a combination of a gravimetric tare weighing and a gross weighing to statistically determine the net weight is particularly well-suited to an intermediate capsule filling device. In addition, such a system is also capable of calibrating a 100% weight testing system 24 on another physical basis (e.g. X-ray).

In the synchronously functioning capsule filling machine, the capsule holder 21 filled with capsules 30 arrives for the removal of the capsules 30 as part of the weighing at station 3. The capsule holder 21 is composed of openings into which the capsules 30 to be transported have been placed. Transport pins 44 are situated underneath these openings and are able to move vertically toward the underside of the capsules 30. In station 3, the capsule holder 21 and the transfer device 42 are situated so that the vacuum openings 40 of the transfer device 42 cover the capsule tops.

As shown in FIG. 3, the transfer device 42 is moved downward toward the capsule holder 21. According to FIG. 4, the transport pins 44 are moved upward to hold the capsules 30 in order to prevent them from coming apart. In addition, a vacuum is supplied to the vacuum bores 40 in order to apply suction to the capsules 30 and lift them out of the openings of the capsule holder 21 (FIG. 5) and, after they have been lifted further, to pivot them to the weighing device 22 (FIG. 6). The above-described arrangement is depicted in a top view in FIG. 7.

The transfer device brings the capsules 30 into alignment with a weighing dish 46 of the weighing device 22. The transfer device 42 lowers all of the capsules 30 into the corresponding openings of the weighing dish 46 (FIG. 9). According to FIG. 10, the first capsule 30 is deposited into the corresponding recess of the weighing dish 46 and to this end, the vacuum supplied to the first vacuum bore is switched off while continuing to be supplied to the other vacuum bores 40. After the transfer device 42 is raised, the tare weight of the first deposited capsule 30 is determined with the aid of a weighing device 22 (FIG. 11). In the next step, the next capsule 30 is deposited into the weighing dish 46 and to this end, the vacuum supplied to the second vacuum bore is switched off (FIG. 12). Then the transfer device 42 lifts the remaining (four) capsules 30 away from the weighing dish 46 in order to enable the weighing procedure of the capsules 30 remaining in the weighing dish 46 (FIG. 13). An evaluation unit determines the tare weight of the second capsule 30 by subtracting the tare weight of the first capsule 30 determined as shown in FIG. 11 from the total weight of the two empty capsules 30. This method repeats for the next capsule 30 to be weighed until all of the capsules 30 have been deposited in the weighing dish 46, as shown in FIG. 14.

The depositing of the capsules into the weighing dish 21 occurs in a fashion analogous to the removal procedure. It is also possible to supply vacuum to the openings that accommodate the capsule bottoms as the capsules 30 are being deposited into the capsule holder 21. This is to provide an improved fixing when the transfer device 42, in the process of depositing of the capsules 30, moves upward away from the deposited capsules 30. The vacuum supplied to the capsule bottoms can also be used to open the capsules 30 if the vacuum is provided to the vacuum bores 40 in parallel with the upward movement of the transfer device 42. This results in the opening of the capsules 30.

The transfer process described above in connection with station 3 is also used at station 9. The additional weighing device determines the gross weight of the filled capsules 30. Based on the tare weight of the capsules determined at station 3, it is possible to determine the net weight of the filling that has been dispensed into each capsule 30. 

1-9. (canceled)
 10. An intermittently operating capsule-filling machine, comprising: a first weighing device that determines the weight of at least one capsule before being filled; a dispensing means for dispensing a substance to be metered into at the least one capsule; and a second weighing device that determines the tare weight of the capsule, by weighing the at least one capsule together with the weight of the substance contained in the capsule.
 11. The device according to claim 10, further comprising at least one transfer device which transfers the at least one capsule to the first and/or second weighing device.
 12. The device according to claim 10, further comprising a capsule holder for transporting the at least one capsule.
 13. The device according to claim 11, further comprising a capsule holder for transporting the at least one capsule.
 14. The device according to claim 12, further comprising at least one transport pin supporting the at least one capsule while the capsule is removed from the capsule holder.
 15. The device according to claim 13, further comprising at least one transport pin supporting the at least one capsule while the capsule is removed from the capsule holder.
 16. The device according to claim 14, wherein it is possible to move the transport pin in a capsule removal direction or in a capsule depositing direction relative to the capsule holder.
 17. The device according to claim 15, wherein it is possible to move the transport pin in a capsule removal direction or in a capsule depositing direction relative to the capsule holder.
 18. The device according claim 11, wherein the transfer device includes means for applying a vacuum to the at least one capsule.
 19. The device according claim 13, wherein the transfer device includes means for applying a vacuum to the at least one capsule.
 20. The device according claim 15, wherein the transfer device includes means for applying a vacuum to the at least one capsule.
 21. The device according claim 17, wherein the transfer device includes means for applying a vacuum to the at least one capsule.
 22. The device according claim 10, further comprising a transfer device including means for applying a vacuum to at least one capsule and at least one transport pin supporting at least one capsule while being removed from a capsule holder.
 23. A method for transferring at least one package to be filled, in particular a capsule, comprising the following steps: preparing the capsule to be removed from a capsule holder; applying a vacuum to a top of the capsule; exerting a force on a bottom of the capsule; and lifting the capsule from the capsule holder through maintaining the vacuum on the top of the capsule while exerting the force on the bottom of the capsule.
 24. The method according to claim 23, further comprising an additional step of depositing at least one capsule in a weighing dish of a weighing device by deactivating the vacuum. 